Electrode support means



Aug. 24, 1965 R. G. SPANGLER ELECTRODE SUPPORT MEANS Filed Feb. 21. 1961 m r m m M T N 0 m m w m S A A B D I m w M Y m NNV u I JNV \N m m 6 11. A M Q\ g m w M O U United States Patent 3,202,861 ELECTRODE SUPPORT MEANS Raymond G. Spangler, Lancaster, Pa., assignor to Radio Corporation of America, a corporation of Delaware Fiied Feb. 21, 1261, Set. No. 90,795 Claims. (Cl. 313-468) This invention relates to a means for electrically insulating electrodes in an electron discharge device. In particular, this invention relates to a means for electrically insulating, while rigidly aflixing electrodes together within a vacuum tube.

There are many known structures for physically supporting electrode elements within a vacuum tube. These support elements are very efiicient for use in certain tube structures such as, for example the small electrodes found in receiving tubes. However, when one attempts to use these known structures to support large diameter electrodes, it is found that the strength of the insulating support structure is not as great as is desired for certain uses. For example, in certain tube types, there are relatively large diameter cylindrical electrodes, e.g. greater than four inches in diameter, which, for electrical purposes must be electrically insulated while being mechanically rigid and mounted in close spaced relationship within-the envelope.

A further problem with the known electrode support means which have been used for electrically insulating, while mechanically supporting, electrode structures is that many of the known structures include various parts which are made of glass. It has been found that glass tends to chip and cause mechanical failure or loose particles within the envelope which are undesirable in certain instances.

It is therefore an object of this invention to provide a novel electrode support means structure.

It is a further object of this invention to provide a means for electrically insulating electrode structures while physically mounting these structures together in a rigid manner.

These and other objects are accomplished in accordance with this invention by providing a metallized ceramic spacer, which is extremely rigid, and which can be readily afiixed to both the outer and inner ones of two nested cylindrical electrodes.

The invention will be more clearly understood by reference to the accompanying single sheet of drawings wherein:

FIG. 1 is a partially schematic sectional view of an electron discharge device, utilizing the invention;

FIG. 2 is an enlarged sectional view of the nested, insulated electrodes shown in FIG. 1;

FIG. 3 is a plan view of an insulating spacer in accordance with this invention and shown in FIGS. 1 and 2; and

FIG. 4 is a sectional view taken along line 3-3 of FIG. 3.

Referring specifically now to FIG. 1, there is shown a direct viewing storage tube 10. The direct viewing storage tube is shown merely to illustrate an example of the type of tube in which it is frequently desirable to mechanically support but electrically insulate large diameter electrodes. Direct viewing storage tubes are commercially available and are described in detail in US. Patent No. 2,856,559 to Knoll. It should be understood that this invention is also applicable to other tube types, such as kinescopes and image tubes, wherein it is desirable to mechanically support and electrically insulate various electrodes.

In particular, the storage tube 10 comprises a writing gun 12 which produces a signal modulated electron beam. The electron beam is scanned over, and writes a charge on an apertured storage screen 14. Adjacent to the writ- 3,202,861 Patented Aug. 24, 1965 ing electron gun 12 is a viewing electron gun 16 which sprays electrons toward the storage screen 14. The viewing electrons pass through the storage screen 14, in the written areas, to develop a visible picture on an adjacent phosphor screen 18. Further details on the particular tube type and its operation may be found in the aboveidentified Knoll patent. The important feature of this tube, so far as this invention is concerned, is to note that several, relatively large, e.g. four inch and greater, cylindrical electrodes 20, 22 and 24 are utilized in order to produce the correct electrical fields for tube operation.

It has been found that these large electrode structures must be very rigidly mounted so that the tube may pass certain vibration and shock tests for particular applications. Thus, in accordance with this invention, the large cylinders 20, 22 and 24 are nested, as shown more clearly in FIG. 2. Between each of the nested cylinders is a metallized ceramic insulating support member 26.

The ceramic insulating support member 26 comprises an annular ceramic spacer 28 which may be made of a material such as a high alumina ceramic. The ceramic spacer 28 may be, for example, A inch in diameter with a 0.180 inch diameter aperture therein and may be approximately .020 inch in thickness. Even though the cylinders 20, 22 and 24 have curved surfaces, and the support members 26 have flat surfaces, due to the relative sizes, the flat support members 26 will make good physical contact with these curved surfaces. T o manufacture insulating support members 26, the planar surfaces of the ceramic member 28 are metallized with a metallizing ink such as molybdenum, or are copper plated by any well known copper plating system. After the ceramic member 28 has been metallized, a bottom plate 30 and an apertured top plate 32, both of which may be made of a material such as a conventional cobalt-iron-nickel alloy, are brazed thereto by any conventional brazing method. The apertured top plate includes a central aperture which is substantially the same diameter as, and is registered with, the aperture in the insulator 28. Also, the apertured top plate 32 includes elongated portions which extend beyond the peripheral edges, in at least one direction, of the ceramic insulator 28. The plates 30 and 32 are thus rigidly fixed to the ceramic insulator 28.

To insert the insulating support member 26 into the various cylindrical electrodes, at least three apertures 36 (shown in FIG. 2) are punched into the outer cylinder, for example cylinder 24, before the cylinders are assembled. The apertures 36 are spaced around the axis of the cylinder. If only three spacers are to be used, spacing between the spacers is preferred. Then, the end portions of the elongated portion of the plate 32 are spot welded to the inner surface of the outer cylinder 24, with each aperture 36 in register with an aperture in one of the plates 32. The inner cylinder 22 is then nested in and properly positioned with respect to the outer cylinder 24. Then, the plate or disc 30 is spot welded to the inner cylinder 22, by passing a welding tool (not shown) through the aperture 36 and into engagement with the disc 30.

Thus, the invention provides a rigid assembly for mechanically supporting while electrically insulating large diameter cylinders. Any number of ceramic spacers 26 may be utilized. However, a relatively large number of such spacers 26 is preferred for relatively large diameter cylinders and for tubes requiring adherence to more rigid vibrational standards.

The principles of this invention can also be utilized to support the electrode cylinders within the envelope. For example, a spring clip 40 (FIG. 1) may be electrically insulated from the cylinder 20 which it supports, by means of an element 26 under each leg of the spring clip 40.

It should be understood that the materials and sizes referred to above are given merely as an example of this invention.

Also, it should be understood that it is not intended to limit theme of this invention to direct a viewing storage tube but the tube 10 is shown merely as an example of a tube structure wherein this invention is particularly useful.

What is claimed is:

1. A sub-assembly for use in an electron discharge device comprising an annular ceramic member and a pair of metallic members, each of said metallic members being fixed to an opposite surface of said ceramic member one of said metal members comprising an imperforate plate closing the openingin said annular ceramic member, the other of said metallic members having an aperture therethrough in register and substantially coextensive with the opening in said annular ceramic member.

2. An electrode support structure for use in an electron discharge device comprising a pair of spaced apart metallic members, one of said metallic members having an opening, and a ceramic insulator interposed between and secured toboth of said metallic members, said ceramic insulator having an opening therein, the other of said metallic members comprising an imperforate plate closing said opening, said opening in said insulator being substantially in register and substantially coextensive with said opening in one of said metallic members, said oneof said metallic members having a dimension larger than said ceramic insulator. I

3. An electron discharge device comprising an evacuated envelope, at least two hollow cylindrical electrodes within said envelope, said electrodes being nested together so that one end portion of one electrode is spaced within an end portion of the other of said electrodes, means to physically connect said electrodes while electrically insulating said electrodes, said means comprising atl east one apertured ceramic member having two opposite sides, said within said device, the larger of said electrodes having at spaced apart regions around the periphery thereof a plurality of apertures, and an insulating support member at eachof said regions, said support member comprising an apertured ceramic member having a pair of disc shaped members brazed thereto, one of said disc shaped members having a dimension larger than that of said ceramic member and having an aperture therein that is substantially in register with the aperture in said ceramic member and in register with one of the apertures in saidlarger cylindrical electrode, said one of said disc shaped members being secured to the inner surface of the larger of said cylindrical electrodes, the other of said disc shaped members being substantially the same size as said ceramic member and closing the aperture in said ceramic member, and said other of said disc shaped members being secured to the outer surface of the smaller of said cylindrical electrodes.

5. The method of physically securing but electrically insulating a pair of electrodes, comprising the steps of providing a plurality of apertures in one of said electrodes, brazing a disc and an apertured disc to the opposite sides of an apertured ceramic member, fixing said apertured disc to an inner surface of said one of said electrodes with the aperture in said apertured disc in register with one of said plurality of apertures in said one of said electrodes, inserting the other of said electrodes into said one of said electrodes, and fixing said disc to an outer surface of said other of said electrodes.

References tCited by the Examiner UNITED STATES PATENTS 1,562,533 11/25 Weintraub 174-1524 2,45 9,277 1/ 49 Halstead et al. 3 1325 0.1 2,459,859 1/ 49 Weston 313-284 X 2,910,607 10/57 McCullough et a1 3l3350 3,073,981 1/63 Miller et al 31382 X DAVID J. GALVIN, Primary Examiner..

ARTHUR GAUSS, GEORGE N. WESTBY, JAMES D.

KALLAM, Examiners. 

1. A SUB-ASSEMBLY FOR USE IN AN ELECTRON DISCHARGE DEVICE COMPRISING AN ANNULAR CERAMIC MEMBER AND A PAIR OF METALLIC MEMBERS, EACH OF SAID METALLIC MEMBERS BEING FIXED TO AN OPPOSITE SURFACE OF SAID CERAMIC MEMBER ONE OF SAID METAL MEMBERS COMPRISING AN IMPERFORATE PLATE CLOSING THE OPENING IN SAID ANNULAR CERAMIC MEMBER, THE OTHER OF SAID METALLIC MEMBERS HAVING AN APERTURE THERETHROUGH IN REGISTER AND SUBSTANTAILLY COEXTENSIVE WITH THE OPENING IN SAID ANNULAR CERAMIC MEMBER. 